1. Field of the Invention
The invention relates to a curtain airbag system.
2. Description of Related Art
A curtain airbag system is known which includes a main inflatable portion provided at a seating location at which an occupant is seated, and an auxiliary inflatable portion that is constantly in fluid communication with the main inflatable portion via a reduced-diameter portion and is located off the occupant seating location (see, for example, Japanese Patent Application Publication No. 2007-161163 (JP 2007-161163 A)). It is also known to provide a curtain airbag with a second deployment portion that extends below the belt line, at a location other than the occupant seating location (see, for example, Japanese Patent Application Publication No. 2007-161167 (JP 2007-161167 A)).
When the curtain airbag is designed to protect an occupant against rollover, the volume of the curtain airbag becomes larger than that of an airbag exclusively used for protection against side impact. In this case, if the capacity of the inflator is increased so that the curtain airbag can be deployed in a short time upon a side impact, a large load is likely to be applied to the head of the occupant when the curtain airbag strikes the head in the course of its deployment.